Piotr referred to India League. I suggest Bha_rata league which
accounts for over 564m. Bha_rata League language speakers.
Top 100 Languages by Population Last updated: February 1999
http://www.ethnologue.com/show_country.asp?name=India
Languages of Republic of India, Bharat. National or official
languages: Assamese, Bengali, Gujarati, Hindi, Kannada, Kashmiri,
Malayalam, Marathi, Oriya, Panjabi, Sanskrit, Sindhi, Tamil, Telugu,
Urdu, English (Associate Official). 1,000,000,000 (1999 IMA).
The population figures in this table refer to first language speakers
in all countries. Note that these figures are updated from the 13th
Edition of the Ethnologue (1996).
Rank Language Name Primary Country Population
1 CHINESE, MANDARIN [CHN] China 885,000,000
2 SPANISH [SPN] Spain 332,000,000
3 ENGLISH [ENG] United Kingdom 322,000,000
4 BENGALI [BNG] Bangladesh 189,000,000
5 HINDI [HND] India 182,000,000
6 PORTUGUESE [POR] Portugal 170,000,000
7 RUSSIAN [RUS] Russia 170,000,000
8 JAPANESE [JPN] Japan 125,000,000
9 GERMAN, STANDARD [GER] Germany 98,000,000
10 CHINESE, WU [WUU] China 77,175,000
11 JAVANESE [JAN] Indonesia, Java, Bali 75,500,800
12 KOREAN [KKN] Korea, South 75,000,000
13 FRENCH [FRN] France 72,000,000
14 VIETNAMESE [VIE] Viet Nam 67,662,000
15 TELUGU [TCW] India 66,350,000
16 CHINESE, YUE [YUH] China 66,000,000
17 MARATHI [MRT] India 64,783,000
18 TAMIL [TCV] India 63,075,000
19 TURKISH [TRK] Turkey 59,000,000
20 URDU [URD] Pakistan 58,000,000
21 CHINESE, MIN NAN [CFR] China 49,000,000
22 CHINESE, JINYU [CJY] China 45,000,000
23 GUJARATI [GJR] India 44,000,000
24 POLISH [PQL] Poland 44,000,000
25 ARABIC, EGYPTIAN SPOKEN [ARZ] Egypt 42,500,000
26 UKRAINIAN [UKR] Ukraine 41,000,000
27 ITALIAN [ITN] Italy 37,000,000
28 CHINESE, XIANG [HSN] China 36,015,000
29 MALAYALAM [MJS] India 34,022,000
30 CHINESE, HAKKA [HAK] China 34,000,000
31 KANNADA [KJV] India 33,663,000
32 ORIYA [ORY] India 31,000,000
33 PANJABI, WESTERN [PNB] Pakistan 30,000,000
34 SUNDA [SUO] Indonesia 27,000,000
35 PANJABI, EASTERN [PNJ] India 26,013,000
36 ROMANIAN [RUM] Romania 26,000,000
37 BHOJPURI [BHJ] India 25,000,000
38 AZERBAIJANI, SOUTH [AZB] Iran 24,364,000
39 FARSI, WESTERN [PES] Iran 24,280,000
40 MAITHILI [MKP] India 24,260,000
41 HAUSA [HUA] Nigeria 24,200,000
42 ARABIC, ALGERIAN SPOKEN [ARQ] Algeria 22,400,000
43 BURMESE [BMS] Myanmar 22,000,000
44 SERBO-CROATIAN [SRC] Yugoslavia 21,000,000
45 CHINESE, GAN [KNN] China 20,580,000
46 AWADHI [AWD] India 20,540,000
47 THAI [THJ] Thailand 20,047,000
48 DUTCH [DUT] Netherlands 20,000,000
49 YORUBA [YOR] Nigeria 20,000,000
50 SINDHI [SND] Pakistan 19,720,000
51 ARABIC, MOROCCAN SPOKEN [ARY] Morocco 19,542,000
52 ARABIC, SAIDI SPOKEN [AEC] Egypt 18,900,000
53 UZBEK, NORTHERN [UZB] Uzbekistan 18,466,000
54 MALAY [MLI] Malaysia, Peninsular 17,600,000
55 AMHARIC [AMH] Ethiopia 17,413,000
56 INDONESIAN [INZ] Indonesia 17,050,000
57 IGBO [IGR] Nigeria 17,000,000
58 TAGALOG [TGL] Philippines 17,000,000
59 NEPALI [NEP] Nepal 16,056,000
60 ARABIC, SUDANESE SPOKEN [APD] Sudan 16,000,000
61 SARAIKI [SKR] Pakistan 15,015,000
62 CEBUANO [CEB] Philippines 15,000,000
63 ARABIC, NORTH LEVANTINE SPOKEN [APC] Syria 15,000,000
64 THAI, NORTHEASTERN [TTS] Thailand 15,000,000
65 ASSAMESE [ASM] India 14,634,000
66 HUNGARIAN [HNG] Hungary 14,500,000
67 CHITTAGONIAN [CIT] Bangladesh 14,000,000
68 ARABIC, MESOPOTAMIAN SPOKEN [ACM] Iraq 13,900,000
69 MADURA [MHJ] Indonesia, Java, Bali 13,694,000
70 SINHALA [SNH] Sri Lanka 13,220,000
71 HARYANVI [BGC] India 13,000,000
72 MARWARI [MKD] India 12,104,000
73 CZECH [CZC] Czech Republic 12,000,000
74 GREEK [GRK] Greece 12,000,000
75 MAGAHI [MQM] India 12,000,000
76 CHHATTISGARHI [HNE] India 10,985,000
77 DECCAN [DCC] India 10,709,800
78 CHINESE, MIN BEI [MNP] China 10,537,000
79 BELARUSAN [RUW] Belarus 10,200,000
80 ZHUANG, NORTHERN [CCX] China 10,000,000
81 ARABIC, NAJDI SPOKEN [ARS] Saudi Arabia 9,800,000
82 PASHTO, NORTHERN [PBU] Pakistan 9,685,000
83 SOMALI [SOM] Somalia 9,472,000
84 MALAGASY [MEX] Madagascar 9,398,700
85 ARABIC, TUNISIAN SPOKEN [AEB] Tunisia 9,308,000
86 RWANDA [RUA] Rwanda 9,306,800
87 ZULU [ZUU] South Africa 9,142,000
88 BULGARIAN [BLG] Bulgaria 9,000,000
89 SWEDISH [SWD] Sweden 9,000,000
90 LOMBARD [LMO] Italy 8,974,000
91 OROMO, WEST-CENTRAL [GAZ] Ethiopia 8,920,000
92 PASHTO, SOUTHERN [PBT] Afghanistan 8,206,000
93 KAZAKH [KAZ] Kazakhstan 8,000,000
94 ILOCANO [ILO] Philippines 8,000,000
95 TATAR [TTR] Russia 8,000,000
96 FULFULDE, NIGERIAN [FUV] Nigeria 7,611,000
97 ARABIC, SANAANI SPOKEN [AYN] Yemen 7,600,000
98 UYGHUR [UIG] China 7,595,512
99 HAITIAN CREOLE FRENCH [HAT] Haiti 7,372,000
100 AZERBAIJANI, NORTH [AZE] Azerbaijan 7,059,000
101 NAPOLETANO-CALABRESE [NPL] Italy 7,047,400
102 KHMER, CENTRAL [KMR] Cambodia 7,039,200
103 FARSI, EASTERN [PRS] Afghanistan 7,000,000
104 AKAN [TWS] Ghana 7,000,000
105 HILIGAYNON [HIL] Philippines 7,000,000
106 KURMANJI [KUR] Turkey 7,000,000
107 SHONA [SHD] Zimbabwe 7,000,000
Part of the Ethnologue, 13th Edition, Barbara F. Grimes, Editor.
http://www.sil.org/ethnologue/top100.html